There are many tools available to you at a free of cost by which you can check your SERP results. Some of them are as follows:
1. Google Analytics
2. Google Webmaster Tool
3. Google PageSpeed Insights
4. Moz Local Listing Score
5. Keywordtool.io
6. Open SIte Explorer
7. Google Keyword Planner
8. Google Trends
9. Quicksprout Website Analyser
10. Schema Creator
11. SERPs Rank Checker
12. SEO site checkup
13. Ahref's Site Explorer
14. Copyscape
15. Robots.txt generator